I found I wasn't wearing my Digimon Vital Bracelet so I turned it into a driving companion! The bumps during driving do allow for some ‘steps’ to be picked up but I'm working on spring bed to better assist with them. 

Buttons and charging port are still easily accessible. 

To fit the VB, you just need to undo both watch bands and the outer casing. When you are at the stage with the screen and the electronics board visible, just slide it into the inner case making sure that the buttons and charging port are correctly aligned. From there all you need to do is slide the inner case into the outer case and you're ready to go! If you want to change your DIM card you can just pop the VB back out easily.

Printed with 10% infill, if you want it to be a bit sturdier a higher infill might be better.